Effects of hyaluronic acid on peripheral nerve scarring and regeneration in rats.
ABSTRACT The purpose of this experimental study was to investigate the effects of topical applications of hyaluronic acid on peripheral nerve scarring and regeneration in an adult rat model. After the right sciatic nerves of 48 rats were transected and immediately repaired, nerves were randomly divided into two groups. Nerves to which were applied hyaluronic acid comprised the experimental group, and nerves to which were applied saline comprised the control group. Perineural scarring was evaluated at 4 and 12 weeks macroscopically and histologically. Nerves treated with hyaluronic acid demonstrated significant reduction in perineural scar thickness (P < 0.05, Student's t-test). Histomorphologic nerve analysis, electrophysiologic studies, muscle mass evaluation, and serial functional walking-track analysis were performed for evaluation of peripheral nerve regeneration at 12 weeks. The results showed better conduction velocities, increased axon-fiber diameter, and faster functional recovery in hyaluronic acid-treated nerves (P < 0.05, Student's t-test). In conclusion, hyaluronic acid appears to be effective in preventing perineural scar formation, resulting in enhancement of peripheral nerve regeneration.
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ABSTRACT: Focal stroke is a disabling disease with lifelong sensory, motor and cognitive impairments. Given the paucity of effective clinical treatments, basic scientists are developing novel options for protection of the affected brain and regeneration of lost tissue. Tissue bioengineering and stem/progenitor cell treatments have both been individually pursued for stroke neural repair therapies, with some benefit in tissue recovery. Emerging directions in stroke neural repair approaches combine these two therapies to use biopolymers with stem/progenitor transplants to promote greater cell survival in the transplant and directed delivery of bioactive molecules to the transplanted cells and the adjacent injured tissue. In this review the background literature on a combined use of neural stem/progenitor cells encapsulated in hyaluronan gels is discussed and the way this therapeutic approach can affect the important processes involved in brain tissue reconstruction, such as angiogenesis, axon regeneration, neural differentiation and inflammation is clarified. The glycosaminoglycan hyaluronan can optimize those processes and be employed in a successful neural tissue engineering approach.Biomatter. 01/2013; 3(1).
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ABSTRACT: Objective (s): Scar formation in injured peripheral nerve bed causes several consequences which impede the process of nerve regeneration. Several animal models are used for scar induction in preclinical studies which target prevention and/or suppression of perineural scar. This study evaluates the translational capacity of four of physical injury models to induce scar formation around the sciatic nerve of rat: laceration, crush, mince and burn. Materials and Methods: Functional (Toe out angle), macroscopic, and microscopic evaluations were performed weekly for four weeks and correlation of findings were analyzed. Result: While macroscopic and microscopic findings suggested a well-developed and adhesive fibrosis surrounding the sciatic nerve, functional assessment did not reveal any significant difference between control and experimental groups (P>0.05). Conclusion: Our study suggests that none of the applied animal models reproduce all essential features of clinical perineural scar formation. Therefore, more studies are needed to develop optimal animal models for translating preclinical investigations.Iranian Journal of Basic Medical Science 07/2013; 16(7):886-90. · 0.24 Impact Factor
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ABSTRACT: A new version of the CatWalk XT system was evaluated as a tool for detecting very subtle alteration in gait based on higher speed sample rate; the system could also demonstrate minor changes in neurological function. In this study, we evaluated the neurological outcome of sciatic nerve injury intervened by local injection of hyaluronic acid. Using the CatWalk XT system, we looked for differences between treated and untreated groups and differences within the same group as a function of time so as to assess the power of the Catwalk XT system for detecting subtle neurological change. Peripheral nerve injury was induced in 36 Sprague-Dawley rats by crushing the left sciatic nerve using a vessel clamp. The animals were randomized into one of two groups: Group I: crush injury as the control; Group II: crush injury and local application with hyaluronic acid. These animals were subjected to neurobehavior assessment, histomorphology evaluation, and electrophysiology study periodically. These data were retrieved for statistical analysis. The density of neurofilament and S-100 over the distal end of crushed nerve showed significant differences either in inter-group comparison at various time points or intra-group comparison from 7 to 28 days. Neuronal structure architecture, axon counts, intensity of myelination, electrophysiology, and collagen deposition demonstrate significant differences between the two groups. There was significant difference of SFI and angle of ankle in inter- group analysis from 7 to 28 days, but there were no significant differences in SFI and angle of ankle at time points of 7 and 14 days. In the Cat Walk XT analysis, the intensity, print area, stance duration, and swing duration all showed detectable differences at 7, 14, 21, and 28 days, whereas there were no significant difference at 7 and 14 days with CatWalk 7 testing. In addition, there were no significant differences of step sequence or regularity index between the two versions. Hyaluronic acid augmented nerve regeneration as early as 7 days after crush injury. This subtle neurological alteration could be detected through the CatWalk XT gait analysis but not the SFI, angle of ankle, or CatWalk 7 methods.Journal of NeuroEngineering and Rehabilitation 04/2014; 11(1):62. · 2.57 Impact Factor